Yamit-Hezi A, Levy Z, Neuman S, Nudel U
Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel.
Gene. 1997 Jan 31;185(1):99-103. doi: 10.1016/s0378-1119(96)00636-1.
A mouse testis cDNA expression library (Clontech) was screened with a synthetic oligonucleotide ligand containing CT-rich motifs derived from the rat skeletal muscle actin gene promoter. These motifs bind nuclear proteins, and seem to be involved in the regulation of the gene. Analysis of isolated clones, which expressed proteins that specifically bind the oligonucleotide, indicated that they were derived from a single gene. This gene was identified as a contaminant of bacterial origin (Leuconostoc lactis). The cloned gene from L. lactis encodes a protein with significant homology to bacterial ribosomal protein S1, which we designated LrpS1-L. Band shift analysis and competition experiments indicated that both the bacterial protein and a mouse nuclear protein specifically bind to the same CT-rich motif of the skeletal muscle actin promoter. Furthermore, antibodies against the recombinant bacterial protein interfered with the formation of complex between the CT-rich element and the mouse nuclear protein. These results indicate that the bacterial LrpS1-L protein and the mammalian protein bind the same CT-rich motif and share common antigenic epitopes.
用一个含有源自大鼠骨骼肌肌动蛋白基因启动子的富含CT基序的合成寡核苷酸配体，对小鼠睾丸cDNA表达文库（Clontech公司）进行筛选。这些基序结合核蛋白，似乎参与了该基因的调控。对分离出的能表达与该寡核苷酸特异性结合的蛋白质的克隆进行分析，表明它们源自单一基因。该基因被鉴定为细菌来源（乳酸明串珠菌）的污染物。来自乳酸明串珠菌的克隆基因编码一种与细菌核糖体蛋白S1具有显著同源性的蛋白质，我们将其命名为LrpS1-L。凝胶迁移分析和竞争实验表明，细菌蛋白和小鼠核蛋白都能特异性结合骨骼肌肌动蛋白启动子的同一富含CT的基序。此外，针对重组细菌蛋白的抗体干扰了富含CT元件与小鼠核蛋白之间复合物的形成。这些结果表明，细菌LrpS1-L蛋白和哺乳动物蛋白结合相同的富含CT基序并共享共同的抗原表位。
